1. Field of the Invention
The present invention relates to a servo controller for driving a feed shaft of a drive mechanism, such as a machine tool, injection molding machine, pressing machine, or the like, and more particularly, to a servo controller suitable for use in cases where the same type of component is to be processed any number of times by a machine tool for processing components.
2. Description of the Related Art
Learning control is already known as a method for increasing processing accuracy and causing control deviation to converge to zero, in cases where processing, or the like, is carried out by repeatedly instructing the same pattern of commands. In the learning control implemented in the prior art, as illustrated in FIG. 2, the same pattern is instructed repeatedly at a uniform pattern cycle, correction data determined on the basis of the positional deviation at each of the control intervals in the previous pattern cycle is stored in a learning memory, and the correction data for each control interval in the previous pattern cycle stored in the learning memory is added to the positional deviation at each of the control intervals of the current pattern cycle, thereby causing the positional deviation to converge to zero (see, for example, Japanese Patent Application Laid-open No. 7-104823 and Japanese Patent Application Laid-open No. 6-309021).
If the cross-sectional shape has the same pattern, and the commands for this same pattern are issued repeatedly, as in a piston lathe, then the learning control described above can be implemented, but if the same pattern is not implemented repeatedly, then learning control of this kind cannot be applied.
In case where many components of the same type are to be processed consecutively, or in case where the same processing shape must be processed at intermittent intervals, many times, learning control has not been applicable, regardless of the fact the commands are of the same pattern because of processing of the same shape.